UNITED NATIONS (AP) — The U.N. chief is expected to present a report on the use of chemical weapons in Syria to the Security Council on Monday morning.

The U.N. inspectors have a mandate to determine whether chemical weapons were used an attack in a suburb of Damascus on Aug. 21 that killed hundreds. However, diplomats have said the report could also point to the perpetrators.

The chief chemical weapons inspector, Ake Sellstrom, has said he will deliver his report on the attack to U.N. Secretary-General Ban Ki-moon in New York this weekend. Two U.N. diplomats said late Friday that Ban would was expected to brief the council about it on Monday morning.

The diplomats spoke on condition of anonymity because the time was not yet final.